<template>
  <div>
    <router-link tag="div" to="/" v-show="showabs" class="header-abs">
      <span class="iconfont header-abs-back">&#xe61e;</span>
    </router-link>
    <div class="header-fixed" v-show="!showabs" :style="opacityStyle">
      <router-link to="/">
        <span class="iconfont header-fixed-back">&#xe61e;</span>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'detailheader',
  data() {
    return {
      showabs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    test() {
      console.log(document.documentElement.scrollTop)
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity: opacity //七分之三不到一的渐变
        }
        this.showabs = false
      } else {
        this.showabs = true
        // 两个横幅直显示一个的逻辑
      }
    }
  },
  activated() {
    window.addEventListener('scroll', this.test)
  },
  deactivated() {
    window.removeEventListener('scroll', this.test)
  }
}
</script>

<style scoped>
.header-abs {
  position: absolute;
  left: 0.2rem;
  top: 0.2rem;
  width: 0.8rem;
  height: 0.8rem;
  line-height: 0.8rem;
  border-radius: 0.4rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.8);
}
.header-abs-back {
  color: #fff;
  font-size: 0.4rem;
  /* color: rgb(17, 0, 255); */
}
.header-fixed {
  z-index: 2;
  /* 盖住滚动式就看不找了 */
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 0.86rem;
  line-height: 0.86rem;
  text-align: center;
  color: #fff;
  background: #00bcd4;
  font-size: 0.32rem;
}
.header-fixed-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 0.64rem;
  text-align: center;
  font-size: 0.4rem;
}
</style>